Great expectations: Historical perspectives on genetic breast cancer testing

Women who test positive for a genetic breast cancer marker may have more th an a 50% chance of developing the disease. Although past screening technolo gies have sought to identify actual breast cancers, as opposed to predispos ition, the history of screening may help predict the societal response to g enetic testing. For decades, educational messages have encouraged women to find breast canc ers as early as possible. Such messages have fostered the papular assumptio n that immediately discovered and treated breast cancers are necessarily mo re curable. Research, however, has shown that screening improves the progno sis of some-but not all-breast cancers, and also that it may lead to unnece ssary interventions. The dichotomy between the advertised value of early de tection and its actual utility has caused particular controversy in the Uni ted States, where the cultural climate emphasizes the importance of obtaini ng all possible medical information and acting on it. Early detection has probably helped to lower overall breast cancer mortalit y. But it has proven hard to praise aggressive screening without exaggerati ng its merits. Women considering genetic breast cancer: testing should weig h the benefits and limitations of early knowledge.